An RF receiver can include a frequency converter for frequency shifting a received RF spectrum, which includes various channels, to obtain an intermediate frequency spectrum in which one or more particular channels are selected. Conversely, an RF transmitter can include a frequency converter for frequency shifting a baseband signal, which includes information to be transmitted, to produce an RF signal.
A frequency converter can include a local oscillator and one or more mixers that are used to up-convert a transmit signal and/or to down-convert a received signal. The local oscillator provides a mixer driver signal, which is a periodical signal having a fundamental frequency. The mixer multiplies an input signal, which includes an input spectrum, by the mixer driver signal. The mixer provides an output signal that comprises a frequency-shifted version of the input spectrum. The fundamental frequency of the mixer driver signal generally determines the desired frequency shift.
One type of frequency converter is a multiphase frequency converter, which includes various mixers. The local oscillator provides various mixer driver signals including at least one mixer driver signal for each mixer. The respective mixer driver signals have a particular phase relationship with respect to each other. For example, a quadrature frequency converter can have two mixers referred to as an in-phase mixer and a quadrature mixer. The respective mixer driver signals for these mixers have a 90° phase relationship with respect to each other.